A 40p indigestion pill taken by millions of Britons could help lift COVID-19 symptoms and speed up recovery, according to new research.

Coronavirus patients on famotidine, sold under the brand name Pepcid, began feeling better within 48 hours - with symptoms clearing up after two weeks.

Doctors in the US are calling for a rigorous clinical trial to see if the medication can combat the pandemic.

Lead author Professor Tobias Janowitz said: "The results of this case series suggest high-dose oral famotidine is well tolerated and associated with improved patient-reported outcomes in non-hospitalised patients with COVID-19."

Major retailers such as Amazon and Walgreens have already experienced shortages after reports elderly survivors in China had been using it.

Now in the first analysis of its kind Prof Janowitz identified a link between Pepcid and speedier recovery among those with mild to moderate coronavirus.

Indigestion

It belongs to a class of drugs known as histamine-2 receptor antagonists which treat acid reflux and heartburn by reducing stomach acid.

Pepcid is available over-the-counter and can be taken in doses of 20 to 160 mg - up to four times a day.

Symptoms began clearing up - in particular cough and shortness of breath - and were gone within two weeks.

Coronavirus patients on famotidine, sold under the brand name Pepcid, began feeling better within 48 hours

Prof Janowitz said: "An outpatient study of oral famotidine that investigates efficacy for symptom control, viral burden and disease outcome and assesses the effects of medication use on long term immunity should be considered to establish if famotidine may be of use in controlling COVID-19 in individual patients while also reducing the risk of transmission."

The ten participants - six men and four women aged 23 to 71 - happened to have been taking Pepcid at the time their infection developed.

They had a diverse range of ethnic backgrounds and known risk factors for COVID-19 severity - including high blood pressure and obesity.

Five major symptoms - cough, shortness of breath, fatigue, headache and loss of taste and smell - as well as general unwellness were measured.

Coronavirus

This was done using a 4-point scale called ECOG PS normally applied to assess the severity of cancer symptoms.

All said they quickly improved within 24 to 48 hours of starting Pepcid and had mostly cleared up after 14 days.

This was evident across all symptom categories assessed but respiratory symptoms such as cough and shortness of breath went quicker than systemic ones like fatigue.

Seven didn't experience any side effects and in the three who did, these were mild - such as temporary forgetfulness.

All started taking Pepcid when they were feeling very poorly with COVID-19 - symptoms of which had been going on for between two and 26 days at that point.

The most frequently used dose was 80 mg taken three times a day, with the average treatment period lasting 11 days, but ranging from 5 to 21 days.

Coronavirus research

Prof Janowitz, of Cold Spring Harbor Laboratory Cancer Center, New York, and colleagues described the results as "promising."

But they pointed out the 'placebo effect' may have played a part as well as hazy recall - added to which the case study was small.

Prof Janowitz said: "Our case series suggests, but does not establish, a benefit from famotidine treatment in outpatients with COVID-19."

It's also not clear how Pepcid might work. It might incapacitate the virus in some way or alter a person's immune response to it.

Prof Janowitz said: "Clinically, we unreservedly share the opinion that well designed and informative studies of efficacy are required to evaluate candidate medications for COVID-19 as for other diseases."

But the findings warrant further more detailed investigation, they said.

Seven of the patients tested positive for COVID-19, using a swab test; two had antibodies to the infection; and one patient wasn't tested but was diagnosed with the infection by a doctor.

Added Prof Janowitz: "Clinically, we unreservedly share the opinion well designed and informative studies of efficacy are required to evaluate candidate medications for COVID-19 as for other diseases."

In April US pharmacy chain CVS ran out of Pepcid in almost all of its New York branches after claims of its effects against COVID-19.

Many locations in Los Angeles, Chicago, Houston, and other cities were also out of stock. A Pepcid packet containing about thirty 20mg tablets costs about £13 ($17).